Micro or nanoscale energy harvesting raises the possibility of creating a technology capable of reducing maintenance costs and inconveniences involving conventional wiring systems. Some ultra-low power energy sources include biological, mechanical vibration, radio frequency electromagnetic, pressure gradients, temperature gradients, solar among others related to renewable energies (Harb, 2011).
The first electronic devices designed to harvest energy were based on passive components that only had the function of recirculating electrons, as the resistors that dissipate power as heat. However, to harness the energy is required to store it in capacitors and then amplify using series and parallel configurations, in this way, the voltage obtained can be useful for some electronic device (Park, 2014).
An alternative that has been proposed to store energy is to use capacitors connected in parallel and then reconfigure the array of capacitors in series to amplify the collected voltage (Logan, 2011) (Logan, 2013).
The present invention addresses the problem of developing and implementing new designs to centralize power in a hybrid energy system once it has been stored.
Some solutions addressed in the state of the art, are described below. For example, Patent Application US 2011/0254514 A1, describes a method and apparatus for converting low voltage and energy storage using a charge pump including a first set of capacitors connected in parallel with a second set of capacitors and switches for selectively coupling the first and second set of capacitors to a variable input DC voltage, with a data processor programmed to control one or more switches for coupling the first and second set of capacitors to a variable input DC voltage for a first variable time period in which first and second set of capacitors are charged to a DC voltage level. An energy storage device is coupled switchable to a matrix output charge pump. The data processor controls by a programmable way one or more switches for coupling the matrix output charge pump to the storage device power for a second variable time period, during which a voltage stored across each capacitor during the first time period, is combined to produce a significantly greater than the DC input voltage, the higher voltage being provided to power storage device.
Another solution has been proposed in the patent application US 2013/0076145 US A1, which describes an electronic circuit to increase voltages of one or more energy sources. The electronic circuit may include a first set of capacitors and a second set of capacitors, and a first set of switches associated with the first set of capacitors and a second set of switches associated with a second set of capacitors. It also includes at least one energy source and an external load. The first and second set of capacitors, first and second set of switches, the power source and the external load are arranged and connected such that the first set of capacitors is connected to at least one power source in parallel while the second set of capacitors is connected to the external load in series and vice versa.
These developments are emerging and are focused on specific energy sources such as thermoelectric and microbial energy respectively, which limits its operating range and current output due to the problem of connecting different ultra-low power sources in parallel configuration, since the behavior of different sources vary in voltage amplitude, oscillation frequency and energy density (Harb, 2011). However, there exist in the state of the art electronic systems that connect each of the various energy sources to a capacitor in parallel and store the energy, once the control system detects the desired voltage for energy transfer then active switches, in order to disconnect the capacitors of them independent energy sources and connecting capacitors in series to each other resulting in the sum of the voltages, i.e.; the present invention describes the design and implementation of an electronic circuit that harvest and/or collects energy from multiple sources of ultra-low power, e.g. mechanical vibration, electrochemical, thermal, etc. Wherein the electronic circuit uses capacitors as initial storage medium and then combined with auxiliary batteries that allow power transfer to a central battery 12 V. This solution allows to integrate energy sources available in different environments, such as: transport, commercial or domestic. Furthermore, the present invention describes the versatility of using energy in systems involving inverters with a nominal input of 12 V in direct current and converts it to alternating current, which can supply energy to a wide range of electrical and electronic devices, such as will be described later in a detailed form.